1. Field of the Invention
The disclosures herein relate to a detector apparatus and a printer having the detector apparatus embedded therein.
2. Description of the Related Art
Certain types of printers feed and print on roll paper (see Patent Document 1, for example). The printer disclosed in Patent Document 1 holds roll paper by supporting its core, and detects the near end of the roll paper based on the result of detecting the outer diameter of the roll paper without regard to a varying size of the core diameter.
The above-noted technology is based on the configuration in which the core of roll paper is supported. This technology is thus not applicable to a drop-in-type printer that employs a support unit for supporting the outer circumferential surface of a paper roll. Further, the detection of a near end (i.e., paper near end) does not take into account a difference in the inner diameter between different paper rolls.
Accordingly, it may be desirable to provide a near-end detector that detects a near end accurately while being applicable to a printer configured to support the outer circumferential surface of a paper roll, and to provide a printer that has such a near-end detector embedded therein. [Patent Document] Japanese Patent Application Publication No. 2011-57435